Organic light-emitting device

Abstract

An organic light-emitting device comprising an anode ( 101 ), a cathode ( 105 ) and an homogeneous organic light-emitting layer ( 103 ) between the anode and the cathode wherein: the light-emitting layer comprises a first light-emitting material mixed with an inert material; the inert material has a HOMO level (HOMO IM ) that is further from vacuum than a HOMO level (HOMO LEM ) of the first light-emitting material and a LUMO level (LUMO IM ) that is closer to vacuum than a LUMO level(LUMO LEM ) of the first light-emitting material; and the inert material comprises up to 25 weight % of the light-emitting layer.

1 . An organic light-emitting device comprising an anode, a cathode and an homogeneous organic light-emitting layer between the anode and the cathode wherein: the light-emitting layer comprises a first light-emitting material mixed with an inert material; the inert material has a HOMO level that is further from vacuum than a HOMO level of the first light-emitting material and a LUMO level that is closer to vacuum than a LUMO level of the first light-emitting material; and the inert material comprises up to 25 mol % of the light-emitting layer. 
     
     
         2 . The organic light-emitting device according to  claim 1 , wherein the first light-emitting material is a fluorescent material and the lowest singlet excited state energy level of the fluorescent material is lower than the lowest singlet excited state energy level of the inert material. 
     
     
         3 . The organic light-emitting device according to  claim 1 , wherein the first light-emitting material is a phosphorescent material and the lowest triplet excited state energy level of the phosphorescent material is lower than the lowest triplet excited state energy level of the inert material 
     
     
         4 . The organic light-emitting device according to  claim 1 , wherein the first light-emitting material is a blue light-emitting material. 
     
     
         5 . The organic light-emitting device according to  claim 1 , wherein the first light-emitting material is a polymer. 
     
     
         6 . The organic light-emitting device according to  claim 5 , wherein the first light-emitting material comprises a repeat unit of formula (IX): 
       
         
           
           
               
               
           
         
         wherein Ar 8 , Ar 9  and Ar 10  in each occurrence are independently selected from substituted or unsubstituted aryl or heteroaryl, g is 0, 1 or 2, R 13  independently in each occurrence is H or a substituent, and c, d and e are each independently 1, 2 or 3. 
       
     
     
         7 . The organic light-emitting device according to  claim 1 , wherein the inert material is a polymer. 
     
     
         8 . The organic light-emitting device according to  claim 7 , wherein the inert material comprises one or more arylene repeat units that may be unsubstituted or substituted with one or more substituents. 
     
     
         9 . The organic light-emitting device according to  claim 8 , wherein the repeat units of the inert material consists of arylene repeat units that may be unsubstituted or substituted with one or more substituents. 
     
     
         10 . The organic light-emitting device according to  claim 1 , wherein the inert material comprises 1-15 mol % of the light-emitting layer. 
     
     
         11 . A formulation comprising a first light-emitting material, an inert material and at least one solvent wherein the inert material has a HOMO level that is further from vacuum than a HOMO level of the first light-emitting material and a LUMO level that is closer to vacuum than a LUMO level of the first light-emitting material, and wherein the inert material comprises up to 25 mol % of the formulation excluding the at least one solvent. 
     
     
         12 . A method of forming the organic light-emitting device according to  claim 1 , comprising the step of depositing a formulation comprising a first light-emitting material, an inert material and at least one solvent wherein the inert material has a HOMO level that is further from vacuum than a HOMO level of the first light-emitting material and a LUMO level that is closer to vacuum than a LUMO level of the first light-emitting material, and wherein the inert material comprises up to 25 mol % of the formulation excluding the at least one solvent onto one of the anode and cathode and evaporating the at least one solvent to form the light-emitting layer, and forming the other of the anode and cathode over the light-emitting layer.